Service management

The majority of snaps expose their functionality via applications that run on the local system. Most of these applications are started either from the command line, the graphical desktop, or as services that run automatically.

A single snap may provide multiple applications and services. With a database snap, for example, you might expect an interactive client application alongside the service daemon.

Snaps manage their own services without the need for manual intervention. However, experienced administrators may want to interact with a snap’s services to help improve their integration with the local environment. For that reason, snapd offers a set of commands to allow a snap’s services to be inspected and their statuses changed.

Listing services

Use snap services to lists all the services added to the system by the currently installed and enabled snaps:

$ snap services
Service                               Startup   Current   Notes
bluez.bluez                           enabled   inactive  -
bluez.obex                            enabled   inactive  -
cups.cups-browsed                     enabled   active    -
cups.cupsd                            enabled   active    -
docker.dockerd                        enabled   active    -
juju.fetch-oci                        disabled  inactive  -
lxd.activate                          enabled   inactive  -
lxd.daemon                            enabled   inactive  socket-activated
lxd.user-daemon                       enabled   inactive  socket-activated
multipass.multipassd                  enabled   inactive  -
nextcloud.apache                      disabled  inactive  -
nextcloud.logrotate                   disabled  inactive  -
nextcloud.mdns-publisher              disabled  inactive  -
nextcloud.mysql                       disabled  inactive  -
nextcloud.nextcloud-cron              disabled  inactive  -
nextcloud.nextcloud-fixer             disabled  inactive  -
nextcloud.php-fpm                     disabled  inactive  -
nextcloud.redis-server                disabled  inactive  -
nextcloud.renew-certs                 disabled  inactive  -

Adding a snap name as an argument will list only those services added by that snap:

$ snap services lxd
Service          Startup  Current   Notes
lxd.activate     enabled  inactive  -
lxd.daemon       enabled  inactive  socket-activated
lxd.user-daemon  enabled  inactive  socket-activated

The output includes the service name, whether the service is started when the system starts up, and whether it’s currently running.

Restarting services

Services are restarted using the snap restart <snap name> command. This may be necessary if you’ve made custom changes to the snap application, for example, which the service needs to reload.

By default, all services for a specified snap will be restarted:

$ sudo snap restart lxd

Using a more specific service name performs the same operation on an individual service:

$ sudo snap restart lxd.daemon

The option to perform an operation on all of a snap’s services, or on one specific service, is common to all commands that operate on services.

If a service supports reloading, enabling the service to remain running while loading a new configuration, this can be requested with the --reload option:

$ sudo snap restart --reload lxd.daemon

Starting and stopping services

The start and stop commands control whether a service should be currently running:

$ sudo snap stop lxd.daemon

$ sudo snap start lxd.daemon

As mentioned above, these commands can operate both on individual snap’s services and on all services for a named snap, depending on the parameter provided.

To prevent a service from starting on the next boot, use the --disable option:

$ sudo snap stop --disable lxd.daemon

The start command includes an --enable option to re-enable the automatic starting of a service when the system boots:

$ sudo snap start --enable lxd.daemon

Inspecting logs

If you need to see the log output for a snap’s services, use the logs command. As with the services command, you can specify either a snap name to see the logs for all the services it contains, or the name of a specific service within a snap:

$ sudo snap logs lxd
2018-09-14T10:38:23Z lxd.daemon[11096]: => LXD is ready

$ sudo snap logs lxd.daemon
2022-07-15T17:13:04+01:00 lxd.daemon[1389234]: => LXD exited cleanly
2022-07-15T17:13:04+01:00 lxd.daemon[370462]: ==> Stopped LXD
2022-07-15T17:13:04+01:00 lxd.daemon[370462]: => Stopping LXCFS
2022-07-15T17:13:04+01:00 lxd.daemon[555302]: Running destructor lxcfs_exit
2022-07-15T17:13:05+01:00 lxd.daemon[370462]: ==> Stopped LXCFS
2022-07-15T17:13:05+01:00 lxd.daemon[370462]: => Cleaning up PID files
2022-07-15T17:13:05+01:00 lxd.daemon[370462]: => Cleaning up namespaces
2022-07-15T17:13:05+01:00 lxd.daemon[370462]: => All done
2022-07-15T17:13:05+01:00 systemd[1]: snap.lxd.daemon.service: Deactivated successfully.
2022-07-15T17:13:05+01:00 systemd[1]: Stopped Service for snap application lxd.daemon.

By default, only the last 10 lines are output. This can be changed with the -n= option which can accept either a number or all for the entire log:

snap logs -n=all lxd.daemon

Adding the -f option will keep log output open so you can follow new entries as they occur:

$ sudo snap logs lxd -f

The size and rate of log output can be limited by placing a snap within a quota group. See Journal log limits for more details.

Last updated 1 year, 10 months ago.